Vladams

Cycad Editing

Article: Cycad

Assignment; March 31st

Add 2-5 sentences of content and 2 citations.

Content:

We will add another subheading named Popular Cycads. This will follow Historical diversity.

The first species to be added will be Cycas revoluta.

• Cycas revoluta is an evergreen cycas with arching leaves as long as 1.5m. This slow-growing plant is a perennial and have a golden-brown inflorescences.

• Cycas revoluta was first found in 1782 in the Ryukyu Islands, Japan.

• It has been found that Cycas reoluta has been introduced to the United States in certain regions of Florida and Georgia.

• For more information, see Cycas revoluta

The second species to be added will be Zamia furfuracea

Another popular species is Zamia furfuracea:

• Zamia furfuracea is mostly found in the country of Mexico.
• There have been studies which found that Zamia furfuracea are pollinated by a small snout weevil, not by the wind (which is the more common reason).
• Zamia furfuracea have 18 chromosomes which is similar to most Central and South American zamias.

Suggested Edits (Peer Review Assignment)

Hi!

Just a few suggestions for your article:

1. Consider the order of the sections. Some parts of the original article don't seem to have a logical or obvious flow. For example, this paragraph in the introduction:

'Cycads are gymnosperms (naked seeded), meaning their unfertilized seeds are open to the air to be directly fertilized by pollination, as contrasted with angiosperms, which have enclosed seeds with more complex fertilization arrangements. Cycads have very specialized pollinators, usually a specific species of beetle. They have been reported to fix nitrogen in association with various cyanobacteria living in the roots (the "coralloid" roots).[6] These photosynthetic bacteria produce a neurotoxin called BMAA that is found in the seeds of cycads. This neurotoxin may enter a human food chain as the cycad seeds may be eaten directly as a source of flour by humans or by wild or feral animals such as bats, and humans may eat these animals. It is hypothesized that this is a source of some neurological diseases in humans.[7][8]"

Could almost be its own (or more than one) section separate to the introduction if you expanded upon it. One section could be on its pollination or reproduction, and one on its symbiotic relationship with cyanobacteria, as well as the neurotoxin that it is produced.

2. Maybe add more on the differences between the three cycad families.

Marioux (talk) 11:08, 6 April 2017 (UTC)

Secondary Compounds

Cycads are very resistant and have been able to survive and continue to survive threats such as droughts, fires, pathogens, and predators. The survival is largely due to the secondary compounds, or neurotoxins, the cycad can create. As mentioned, these compounds can protect the cycad against predators, so the compounds affect those that eat the cycad. These compounds are believed to cause Zamia Staggers in cows and sheep that graze on the cycads. It is also thought that it could be related to an increases in Parkinson's Dementia and Alzheimer's in people who eat them (often in the form of flour). This is also known as Guam's Dementia.

In the roots of cycads live cyanobacteria. These photosynthetic bacteria produce a neurotoxin called BMAA that can be found in the seeds of cycads. This specific neurotoxin is related to the previously mentioned neurological diseases in both humans and animals.

Evolutionary History

Cycads originated an estimated 275-300 million years ago, with the oldest known fossils dating back to the Upper Paleozoic.

The recognizable morphological characteristics the cycads had during evolution, help in understanding the evolution of angiosperms and gymnosperms.

Leaf Evolution

Cycads currently have compound leaves, and they developed independently from the flowering plants. This is a result of leaf complexity being reduced. The result of this evolution is believed to have lead to angiosperm leaves.

Evolution and Seed Plant Diversity

There are three major hypotheses for seed plant diversity:

1. Plant diversity increases when plant pollination is done by an insect
2. Plant diversity increases when animals disperse the plant’s seeds
3. When plants keep evolving to defend themselves against their predators, such as insects

Cycads fit into all three of these, and if the hypotheses were correct they should have had a very large increase in diversity over the past 300 million years. However, Cycads have had very little diversity. They have radiated much less then flowering plants, resulting in only 2 or 3 extant families and 100-150 extant species over time. This is much less diverse than the flowering plants, which have developed approximatley 413 extant families and over 200,000 extant species over the past 125 million years. Although they lack diversity, that does not mean they are not diverse, in fact cycads are much more diverse today than ever before. They have a much greater taxonomic and morphological diversity.

Vladams (talk) 17:11, 11 April 2017 (UTC)

Conservation Status

With 63% of the cycad species assessed with the threat of extinction, cycads are the world’s most threatened group of plants. Since Africa has the most diversity of cycads, it has been considered the region with the greatest threat to cycad population. Out of all of the taxa in Southern Africa, 25 are classified as threatened which include 10 which are critically endangered. Some species are long lived and because of this, they cannot adapt to their surroundings as rapidly compared to a younger lived species. This is a severe flaw because it can prevent speedy adaptation and lead to the decease of a species over time. Many endangered cycads are protected in native countries through various laws and policies. For international circumstances, cycads are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the World Bank's Project: Save Our Species

Dmvasconcelos (talk) 21:44, 13 April 2017 (UTC)